Over the past three decades, improved testing and treatments may prevent hundreds of thousands of women from dying of breast cancer, computer simulations offer.
According to the simulation, anywhere from 305,000 to more than 600,000 breast cancer cases may have been avoided, researchers reported in Cancer.
Since no one knows how many women would die without progress in screening and treatment, the researchers developed estimates of trends in breast cancer based on information collected prior to 1990.
"The number of women per 100,000 years who died each year between 1975 and 1990 – before the extensive screening of radiation – increased slightly from year to year," said Dr. Jay Baker, a professor of radiology at Duke University. . "There are a number of assumptions you can make about the maximum mortality rate. For example, you could say that it was flat after 1990 or you could say it kept growing at the same rate that was between 1975 and 1990, or you could say it was more and more. "
In the new study, Baker and his colleagues turned to data from the National Cancer Institute's surveillance, epidemiology and termination program to assess how many women between the ages of 40 and 84 died of breast cancer each year before 1989. SEER collects data on cancer diagnosis, treatment, and survival, 30 percent of the US population.
First, they hypothesized four ways that history could have been done had the radiation and treatments not been advanced. (For example, the number of deaths from breast cancer remained constant after 1989, or mortality rates increased by 0.4% per year since 1989, etc.).
They then subtracted the annual number of deaths as calculated from SEER data from the number of deaths predicted by their simulations. The number obtained, Baker said, was the number of deaths that had been avoided.
According to the scenario used, the number of deaths from breast cancer shifted between 1990 and 2018 ranged from 305,000 to 61,4,500.
The new findings should be interpreted in light of the number of assumptions used by the researchers, said Dr. Diana Atai, a clinical assistant professor in the Department of Surgery at the David Geffen School of Medicine at the University of California Los Angeles. Los Angeles and UCLA Health and Burbank Breast Care.
Another weakness of the study is that SEER data were available only through 2015, and the researchers used this information to assess the death rates going forward.
"I do not think any of us will doubt that improvements in radiation therapy and improvements in treatment have led to better results," Attai said. "But you have to consider the fact that they do not have real data from 2016, 2017 and 2018. And you have to consider the fact that SEER data does not include every single woman who died of breast cancer."
While SEER's database is very useful, it has changed over the years to become more of a complex of different parts of the country as well as minorities, Attai said. That is, sampling from 20 years may be different in recent years.
Beyond that, Attai says, there is no information in the SEER database on whether women received mammograms within a year diagnosed with breast cancer. It is therefore impossible to say, based on this database, what the effect of irradiation on death declines.
"Such studies are at most guests," Attai said.
"I am most interesting in the 2017 years until 2019 since this is when there is tremendous progress in targeted treatments," she said.
Source: cancer bit.ly/2GnFeIn, online February 11, 2019.